Good chicken stock
Onion finely chopped
Dark Portobello mushrooms, cooked in butter
Salt and pepper, to taste
Fresh thyme
Fresh parsley, finely chopped
Method
Cook ingredients almost to a paste
Dust in flour
Pour in hot stock, salt and pepper, fresh thyme.
Simmer away
Skim or rest over night
Add toasted walnuts (not chopped too finely) at the last minute.